Your suggestion merely echoes what the club has done for years hence it does not, nor cannot, work as proven by our lamentable failure to provide the team with home grown talent.
Obviously if a trainer sees a talent that might be suited to a different position he will change that position but the player concerned should be told clearly that such positional changes are few.
I also think that in most cases a future star is apparent at an early stage, such players should get time on the first team bench.
One oddity has occurred to me who was the last home grown keeper we've produced, is it Andy Rankin all those years ago?